Jellying pectin compositions



UNITED s'rATEs JELLYING PECTIN COMPOSITIONS George L. Baker and, Marvin W. Goodwin, Newark, Del., assignors to the Public oi! .the

United States No Drawing. Continuation of application Serial No. 258,191, February 24, 1939. This application August 9, 1939, Serial No.289,l24

' 3 Claims. (01. 99-132) This invention relates to'the preparation oi powdered pectin compositions which will form jellies with or without added sugars, acids, flavorin: or coloring materials. This is a continuation 5 of our application, Serial No. 258,191, filed. Februmy 24, 1939. I

Tarr and Baker, Bulletin 136 (1925) Delaware Agricultural Experiment Station, described a pectin-acid compound, a partially demethoxy- 1o lated pectin with free acid radicles, which produced jellies with less than 50% soluble solids as sugar. Non-sugar Jellies of pectin are also known, that is, gelation of aqueous pectin systems by the action of the enzyme pectase in thepresll ence of metallic salts (Kopaczewski, Bull. Soc.

Chim. Biol. 7, til (1925)),gelation of calciumiree pectin" solutions upon adding CaClz (Waele, Ann. Physiol. et Physicochim. Bio. 5, 86s (1939))- or the ammonium and potassium salts oivpectic acid which produced jellies :for Braconnot (Ann.

chim. phys., 28, 1'73, (1825) l However, no powdered pectin composition has been known which will jelly without added sugar, glycerin, or similar dehydrating agent upon adding water or fruit as juices followed by heating and cooling. Nor has a sugar-less pectin telly with low temperature inciting points and the ability to reset to a jelly over a wide pH range heendescribezl.

An object 0! this invention is to preparepectin compositions which can be used in lieu of animal gelatin or agar-s. A particular object is to prepare a pectin product which is suitable for food. purposes, i. e., salads and desserts. .Other and important objects will become apparent ironi the following. description and appended claims.

This invention is based upon the discovery that partially demethomlated pectins, prepared in the absence oi metallic salts or organic compounds known to aid .iellation, when located with water in the presence oi small amounts of these same metallic salts or organic compounds which aid .iellation will form jellies upon coolinc.

tins extracted at low temperatureafill" C. or below, lose their inethorzyl content without excessive depoiymerlzatlon of the pectin molecule more easily than pectins extracted at higher ternperatures. These low methcxyl pectins will have a propor-tionately'hlgher concentration 'of free carboxyl groups, which means that they will combine more readily with metallic ions and he more easily precipitated. This forms the basis of certain methods of pectin recovery. The pectin to be tound in our composition has been partially demethoxylated; the tree carboxyl groups have a not been allowed to react with metallic ions, but

have been allowed to react with the weak base, ammonia. Upon adding sumcient ammonia to neutralize extraction acidities, viscosities are depressed in the pH range 3.5 to 7, allowing easy' filtration and clarification. Dehydration or precipitation and drying of the pectin in this extract produces ammonium pectinate. When this pectinate is dry-mixed with certain other salts, such as those of calcium which are known to aid jella tion or even to precipitate partially demethoxylated pectins, compositions are formed which will jelly upon adding water, heating and cooling. The heating in the presence of a salt which is known to aid jellylng, causes the NH4 ion to split off and a metallic pectinate to form and the mass jellies upon cooling. The amount of metallic salt added must be insufficient to satisfy the re duirements oi the free carhoxyl groups, or imme- .diate precipitation. oi the mass will takeplace.

Other weak bases such as bicarbonate of soda which do not contain a substance known to aid jellation of pectin jellies can be used. Strong bases, NaOl-l and KOH, have been used to new tralize extraction acidities and the salts formed depress viscosities in a similar pH range to that used with ammonia but the jellies formed after using these bases were unsatisfactory in appear ance and strength. The sheet of various salts upon viscosity of pectin solutions is described by Baker and Goodwin. Bulletin 216 (1939'), Delaware Agricultural Experiment Station.

Apple pomace and citrus albedo have been used in preparing this pectin composition. It is prs ierred practice to first remove solubles in either case by a hot leach treatment as described'in Bulletin 2% (1936) Delaware Agricultural E periment Station or in U. 5. Patent No. 2,088,456 (1937). The moist, leached material is then treated with acid at a temperature below 68 C2. the time and pH of this treatment being inter-- dependent, but the concentration of leached material is of no importance. At the end of this acid treatment which hydrolyzes protopectin to soluble pectin and demethoxylates but does not substantially depolymerize the pectin, the mix ture is neutralized to pl-I 3.5 to 7, preferably to pH 4.5, using concentratedNHrOH while agitating. The inert fibrous material is then separated by expressing or filtering oil the pectinextract which can he clarified if desired. The pectin in the extract is recovered by dehydration or precipitation. The dried pectin product when dry mixed with edible salts suchas calcium citrate, calcium tartrate, calcium phosphate. and calcium gluconate, or with salts such as those of alum-- (1931) and Bull. 187 (1934) of the Delaware Agricultural Experiment Station and are so numerous that if disclosure were to cover all cases data would be endless. The necessary pH values forcarrying out the demethoxylaobtained with hydrochloric, nitric and phos- I phoric .acids. The limiting range of pH for the acid extraction and depolymerization of pectin is governed by the economics of the process but, in general, extractions are below pH 2. At 60 C., with the extraction medium at pH 1.5, approximately 72 hours are required for the extraction and depolymerization reaction, while with the extraction medium at pH 0.5 only approximately 4 hours are required for the same accomplishment. The higher pH is preferred. Thus at the higher concentrations of acid, the tem-' perature of extraction being the same, con-' version of protopectin to soluble pectins and their demethoxylation is most rapid. At the I same concentration of acid/the rate of extracperature increases.

tion and demethoxylation increases with tem- Conditions "where depoly- I merization of the pectin is more rapid than demethoxylation are to be avoided. .If pectin has been extracted without demethoxylation, or, if source of material is a pectin preparation, other known methods of demethoxylation, such as the use of low concentrations of alkali, which creates pH values of 5.to6 can be employed.

The pectin present in the composition is not pectic. acid which is demethoxylated and depolymerized poly'galacturonio acid. The percentage of methoxyl in the pectin ranges from the approximate limits of 3 and 6.5 as determined by saponification in accordance'with directions in Bulletin 187 of the Delaware Agricultural .Experiment Station. The optimum methoxyl content is 4.5%. The galacturonic acid content approximates to for apple pectins and '70 to for citrus pectins. These pectins are not depolymerized polygalacturonic acid because they are characterized by the development of high viscosities in dilute water solution at certain pH values. The pH-viscosity curve is characterized by definitepeaks at pH 3 1325 gm. water at 56 C; for '72 hours.

Seventy-five grams of pomace, 1 mm. particle T size, was heated with 100 gm. N/l HCl and The pH at the end of the extraction period equalled 1.45

'as measured with the glass electrode at 25} C.

The batch was neutralized to pH 4.5 with con- I centrated NH4OH while stirring and then clarifled using a filter-aid and suction. The extract was precipitated in twice its volume of ethyl alcohol. The precipitate was dried at 60 C. A.

0.5% solution of this pectin had a pHv of 5.13

, pH 3.5 and 3, the preferred range.

' Sugar and.other agents have v aid dispersion of the composition but are not prevents further loss of'juice.

i fruits which were frozen.

and a relative viscosity of 4.16 at 26 0., at pH 2.9 the viscosity was 6.01,.and at pH 1.9. the-vis-f cosity was 3.62. A sample composition, made by dry-mixing 5 partsof this pectin, 1 part. 01' calcium monophosphate, 0.5 part of tartaric acid and 20 parts of sugar to aid dispersion, when ,heated to boiling with 500 parts water, with stirring, and then cooled in the refrigerator,

formed tender jellies with a jelly strength of 26 to 28 cm. water pressure at pH 3.45. Greater juice, lemon juice, orange juice and canned cherry juice are among the juices which have been added to a sample composition and jellied upon heating the mixture to boiling while stirring and then cooling in the refrigerator.

Specific and valuable properties imparted to jellies bythe composition are low melting points, evenas lowas room temperature or below, and the ability to rejelly upon chilling. Temperature at which thejellies will melt is varied by 25 varying the components-the salt, the acid and the pectin.

can be varied, but, in general, especially with The proportionate partsof pectin, salt and acid which make up the composition the pectin of higher methoxyl content, as the proportion of acid is raised that of the salt must also be raised in order to form satisfactory jellies. I have been varied so that jellies have formed throughout the pH range 4.16 to 2.58, the

been added to clearest, most sparkling jellies forming between necessary. Protective coatings can be applied to the pectin particles to aid dispersion or-preser- The components of the composition vation. Sugar, flavoring materials, coloring mato the composition and satisfactorily jellied. Higher concentrations of sugar and even the high concentration of soluble solids as sugar in The procedure of adding water .or fruit juice, heating to boiling, and then cooling can be varied. The dispersingllquid need only be held above the melting point of the composition in terials, and dried fruit products have been added 1 order that the solution, will jelly upon chilling.

, A modification of this invention is found'when the pectin, ammonium pectinate, used in this composition is applied to soft fruits, e. g., strawberries, cherries, etc., before freezing. The pectin is suitably standardized with su arsxand It has "been a coloring materials, if necessary. found to retard the loss of juice from the. fruit 'upon thawing for use. As theijuice'is released from the cells of the fruit and contacts the added pectin a jelly-like coating is formed 'by the action of the fruit salt upon the pectin'whi ch This action is similar to the addition of salts favorable to jellying to the dispersing liquid instead of to the composition, the salts being obtainedfrom the Other modifications and .variations in the components making up the composition will readily occur'to'those skilled in the art. These methods and modifications of the invention are: limited only by the scope of the mason l. The process of producing powdered ,ieliying pectin compositions, comprising, incorporation, in the dry state, of soluble pectins with a methoxyl content oi between 3 and. 6.5per cent 'and a solution pH of 3.5 to 7.0 with a salt of at least one of the metals from the group consisting of aluminum, calcium, iron, manganese, and nickel, which .will form jelly solely upon adding many times their weight-o! water followed by heating to boiling and cooling.

2. The process of producing powdered Jellying pectin compositions, comprising,- incorporation, in the dry state, of soluble pectins with a methoxyl content 01' between 3 and 6.5 per cent and a solution pH of 3.5 to 7.0, with an edible calcium salt, with organic acids. with flavoring 3 materials, and with coloring materials, which will form Jelly solely upon adding water followed by heating to boiling and cooling. v

3. The process of producing powdered jeliying pectin compositions, comprising, incorporation, in the dry state, 01' soluble pectins with a methoxyl content of between 3 and 6.5 percent and a solution pH 01 3.5 to 7.0, with an edible calcium salt, and with an organic acid, which will form Jellies solely upon adding water at a temperature above the melting P int oi the composition and chilling the. dispersed phase, the

resulting jellies being characterized by low melt-1 ing points and the ability to reset upon cooling.

' GEOR,GE L.

W.- GOODWIN. 

